Page created Aug 25, 2021|
Last updated Aug 27, 2021
Despite a considerable effort on the part of Dreyer and his predecessors and contemporaries, modern historical research has discovered that there were many "nebulae" and star clusters discovered before the publication of the New General Catalogue
that were never included in any of Dreyer's catalogs. Corwin and his colleagues have listed these as "notngc" objects, and the purpose of this page (and as time allows, additional pages) will be to turn the basic historical and positional data into the same sort of thorough catalog as the NGC/IC catalog that I have been working on for the last 12 years (and expect to continue working on for most if not all of the rest of my life). So far, only one object in the notngc.dat file had been placed in my NGC/IC catalog, and its entry has now been moved to this page. As I have time I will add others, and hopefully eventually have as complete a catalog of those objects as possible.
It should be noted that many of these objects will almost certainly be in one of the various supplementary catalogs on my website, and where that is true, this page (or pages, when necessary) will only present historical information, and provide links to the pages where physical data and images of the objects are already located.
Until this/these page(s) are complete, refer to Harold Corwin's website for a complete list of currently known notngc objects (continually updated as the various individuals involved in the historical research run across previously 'lost' information):
A list of known notngc objects and their J2000 positions
A historical discussion of the objects' discovery, and how modern research has revealed their original discovery
Barnard's Andromeda OB, part of the Andromeda Galaxy
Recorded (Oct 8, 1885) by Edward Barnard
An OB association in Andromeda (RA 00 44 33.4, Dec +41 52 20)
Historical Identification: Barnard's Andromeda OB association (1860 RA 00 36 53, NPD 48 54.6) is "small, faint, near eastern end of M31, 17.1 arcmin north and 29 seconds east of 9th magnitude star W2 0h952, southeast of small star" (the 1860 position having been obtained by precessing Barnard's 1885 position). Barnard's original position precesses to J2000 RA 00 44 32.9, Dec +41 51 23, well within the OB association listed above, 17 arcmin north and 29 seconds east of magnitude 9.0 star BD+40 151, and southeast of a 13th magnitude star, so the identification is certain.
Discovery Notes: As noted by Corwin, such an observation would normally have been given an NGC entry by Dreyer, but in this case it was not, hence its inclusion in his "notngc" list. The "date recorded" is based on Barnard's note of Oct 9, 1885, in which he says "I have for some time suspected a faint Nebula near the (eastern) end of the Great Nebula in Andromeda. Last night being fine I verified its existence." This suggests that he had already observed the region on numerous occasions, but only took the time to carefully observe and record the position on Oct 8, 1885.
Physical Information: Given the 2.54 million light year distance of the Andromeda Galaxy, the association's apparent size of 4.1 by 1.8 arcmin corresponds to 3000 light years.
Above, a ? degree wide image of the Andromeda Galaxy showing the location of Barnard And OB
(Image Credit Bill Schoening, Vanessa Harvey/REU program/NOAO/AURA/NSF)
Below, a 15 arcmin wide DSS image centered on Barnard And OB
Below, an 8 arcmin wide SDSS image of the association
(= CGCG 238-051)
Discovered (Jan 9, 1856) by R. J. Mitchell
A magnitude 15(?) lenticular galaxy (type E/S0?) in Ursa Major (RA 09 25 00.4, Dec +49 22 37)
: Per Gottlieb, this object was noted by Mitchell in his description of his observations of what later became NGC 2854
, in which he notes the presence of another nebula (which became NGC 2857
), and about 5 arcmin "following" (to the east of) that nebula, perhaps "another very small knot with 2 stars preceding (west) and north?" That position and description is a good fit to the galaxy listed above, which is just under 4 arcmin east-northeast of NGC 2857, and does indeed have stars to its west and north, so although Dreyer did not include it in the NGC, it was certainly discovered by Mitchell as noted above.
: Corwin notes that although mentioned in the observation of Jan 9, 1856, this object was not
mentioned in observations made at Birr Castle in March 1858 and March 1867, which may have made Dreyer think that the first "observation" was not sufficiently certain to justify including the object in the NGC.
: Based on a recessional velocity relative to the Cosmic Background Radiation of 8390 km/sec (and H0
= 70 km/sec/Mpc), a straightforward calculation indicates that PGC 26694 is about 390 million light-years away. However, for objects at such distances we should take into account the expansion of the Universe during the time it took their light to reach us. Doing that shows that the galaxy was about 375 to 380 million light-years away at the time the light by which we see it was emitted, about 380 to 385 million years ago (the difference between the two numbers being due to the expansion of the intervening space during the light-travel time). Given that and its apparent size of about 0.65 by 0.4 arcmin (from the images below), the galaxy is about 70 thousand light-years across.
Above, a 12 arcmin wide SDSS image centered on NGC 2857, also showing "NotNGC" object PGC 26694
Below, a 0.8 arcmin wide composite PanSTARRS/SDSS image of PGC 26694